Level 54

Total Experience Required 816,062

Level 100 progress: 11.96%

This is roughly the same as:

Killing 1,361 people in Warzone, or...
Killing 1,388 people in Execution, or...
Killing 1,153 people in Wingman, or...
Scoring 291,451 points in Guardian, or...
Scoring 887,024 points in Annex, or...
Scoring 536,883 points in Submission.

Horde (TU4)

Completing 2,041 waves on Casual, or...
Completing 1,361 waves on Normal, or...
Completing 1,021 waves on Hardcore, or...
Completing 817 waves on Insane.

Or a combination of the above. Have fun!